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3-2.2 Structural Members.
The installation of air ducts, including the hangers, shall not reduce the fire resistance rating of structural members.
3-2.3 Ceiling Assemblies.
Where the installation of the hangers for the components of an air duct system penetrates an existing ceiling of a fire-resistive floor- or roof-ceiling assembly and necessitates removal of a portion of that ceiling, the replacement material shall be identical to or approved as equivalent to that which was removed.
Exception: As an alternative to repairing the existing ceiling, a new ceiling shall be permitted to be installed below the air duct system, provided the fire resistance rating of the floor- or roof-ceiling design is not reduced.
3-3* Penetrations ?Protection of Openings.
3-3.1 Fire-Rated Walls and Partitions.
3-3.1.1*
Approved fire dampers shall be provided where air ducts penetrate or terminate at openings in walls or partitions required to have a fire resistance rating of 2 hours or more.
Exception*: Fire dampers shall not be required where other openings through the wall are not required to be protected.
3-3.1.2
Approved fire dampers shall be provided in all air transfer openings in partitions that are required to have a fire resistance rating and in which other openings are required to be protected.
3-3.2 Floors Required to Have a Fire Resistance Rating.
Where air ducts extend through only one floor and serve only two adjacent stories, the air ducts shall be enclosed (see 3-3.4.1) or fire dampers shall be installed at each point where the floor is penetrated.
Exception: Air ducts serving air-conditioning terminal devices on the floor above, provided a fire test conducted in accordance with NFPA 251, Standard Methods of Tests of Fire Endurance of Building Construction and Materials, determines that the fire resistance rating of the floor is maintained.

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3-3.3* Floor- or Roof-Ceiling Assemblies Having a Fire Resistance Rating.
Where air ducts and openings for air ducts are used in a floor- or roof-ceiling assembly that is required to have a fire resistance rating, all the materials and the construction of the assembly, including the air duct materials and the size and protection of the openings, shall conform with the design of the fire-resistive assembly, as tested in accordance with NFPA 251, Standard Methods of Tests of Fire Endurance of Building Construction and Materials. (Where dampers are required, see 3-4.4.)
3-3.4 Shafts.
3-3.4.1
Air ducts that pass through the floors of buildings that require the protection of vertical openings shall be enclosed with partitions or walls constructed of materials as permitted by the building code of the authority having jurisdiction. The enclosure shall have a minimum fire resistance rating (based on possible fire exposure from either side of the partition or wall) of 1 hour where such air ducts are located in a building less than four stories in height and a minimum rating of 2 hours where such air ducts are located in a building four stories or more in height.
Exception: Where an air duct penetrates only one floor, or one floor and an air-handling equipment penthouse floor, and the air duct contains a fire damper located where the duct penetrates the floor, an air duct enclosure shall not be required.
3-3.4.2
A fire-resistive enclosure used as an air duct shall conform with 2-3.1 and 3-3.4.1. Gypsum board systems shall be constructed in accordance with the Gypsum Association Fire Resistance Design Manual.
3-3.4.3
Shafts that constitute air ducts or that enclose air ducts used for the movement of environmental air shall not enclose the following:
(1) Exhaust ducts used for the removal of smoke- and grease-laden vapors from cooking equipment
(2) Ducts used for the removal of flammable vapors
(3) Ducts used for moving, conveying, or transporting stock, vapor, or dust
(4) Ducts used for the removal of nonflammable corrosive fumes and vapors
(5) Refuse and linen chutes
(6) Piping
(7) Combustible storage
Exception: Noncombustible piping conveying water or other nonhazardous or nontoxic materials.

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3-3.4.4
Fire dampers shall be installed at each direct or ducted opening into or out of enclosures required by 3-3.4.1.
Exception No. 1: Where an air duct system serving only one story is used only for exhaust of air to the outside and is contained within its own dedicated shaft.
Exception No. 2: Where branch ducts connect to enclosed exhaust risers meeting the requirements of 3-3.4.1 or 3-3.4.2 in which the airflow moves upward and steel subducts at least 22 in. (56 cm) in length are carried up inside the riser from each inlet and the riser is appropriately sized to accommodate the flow restriction created by the subduct.
3-3.5 Smoke Barriers.
3-3.5.1
Smoke dampers shall be installed at or adjacent to the point where air ducts pass through required smoke barriers, but in no case shall a smoke damper be installed more than 2 ft (0.6 m) from the barrier or after the first air duct inlet or outlet, whichever is closer to the smoke barrier.
Exception No. 1: Smoke dampers shall not be required on air systems other than where necessary for the proper function of that system where the system is designed specifically to:
(a) Function as an engineered smoke-control system, including the provision of continuous air movement with the air-handling system
(b) Provide air to other areas of the building during a fire emergency
(c) Provide pressure differentials during a fire emergency
Exception No. 2: Smoke dampers shall not be required to be located within a prescribed distance of a smoke barrier where isolation smoke dampers are used in air-handling equipment. (See 2-3.9.2.)
Exception No. 3: Smoke dampers shall not be required where the air inlet or outlet openings in ducts are limited to a single smoke compartment.
Exception No. 4: Smoke dampers shall not be required in ducts where the air continues to move and the air-handling system installed is arranged to prevent recirculation of exhaust or return air under fire emergency conditions.
Exception No. 5: *Smoke dampers shall not be required in health care occupancies where exempted by NFPA 101? Life Safety Code?
3-3.5.2
Where penetration of a smoke barrier is required to be provided with a fire damper, a combination fire and smoke damper equipped and arranged to be both smoke responsive and heat responsive shall be permitted

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3-4 Fire Dampers, Smoke Dampers, and Ceiling Dampers.
3-4.1
Fire dampers used for the protection of openings in walls, partitions, or floors with fire resistance ratings of less than 3 hours shall have a 11/2-hour fire protection rating in accordance with UL 555, Standard for Safety Fire Dampers.
3-4.2
Fire dampers used for the protection of openings in walls, partitions, or floors having a fire resistance rating of 3 hours or more shall have a 3-hour fire protection rating in accordance with UL 555, Standard for Safety Fire Dampers.
3-4.3*
Smoke dampers used for the protection of openings in smoke barriers or in engineered smoke-control systems shall be classified in accordance with UL 555S, Standard for Safety Smoke Dampers.
3-4.4
Ceiling dampers or other methods of protecting openings in rated floor- or roof-ceiling assemblies shall comply with the construction details of the tested floor- or roof-ceiling assembly or with listed ceiling air diffusers or listed ceiling dampers. Ceiling dampers shall be tested in accordance with UL 555C, Standard for Safety Ceiling Dampers.
3-4.5 Damper Closure.
3-4.5.1
All fire dampers and ceiling dampers shall close automatically, and they shall remain closed upon the operation of a listed fusible link or other approved heat-actuated device located where readily affected by an abnormal rise of temperature in the air duct.

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-4.5.2
Fusible links shall have a temperature rating approximately 50癋 (28废) above the maximum temperature that normally is encountered when the system is in operation or shutdown, but not less than 160癋 (71废).
Exception: *Where combination fire and smoke dampers are located within air ducts that are part of an engineered smoke-control system, fusible links or other approved heat-responsive devices shall have a temperature rating approximately 50癋 (28废) above the maximum smoke-control system designed operating temperature but shall not exceed the UL 555S, Standard for Safety Smoke Dampers, degradation test temperature rating of the combination fire and smoke damper or a maximum of 350?F (177废).
3-4.5.3
A provision for remote opening of combination fire and smoke dampers, where necessary for smoke removal, shall be permitted. Such dampers shall have provisions that allow them to reclose automatically upon reaching the damper抯 maximum degradation test temperature in accordance with UL 555S, Standard for Safety Smoke Dampers.
3-4.5.4*
Dampers shall close against the maximum calculated airflow of that portion of the air duct system in which they are installed. Fire dampers shall be tested in accordance with UL 555, Standard for Safety Fire Dampers. Smoke dampers shall be tested in accordance with UL 555S, Standard for Safety Smoke Dampers.
Exception: Where provisions for automatic fan or airflow shutdown, in the event of a fire, are provided.

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3-4.6 Installation.
See 2-3.4 for access.
3-4.6.1
The locations and mounting arrangement of all fire dampers, smoke dampers, ceiling dampers, and fire protection means of a similar nature required by this standard shall be shown on the drawings of the air duct systems.
3-4.6.2*
Fire dampers, including their sleeves; smoke dampers; and ceiling dampers shall be installed in accordance with the conditions of their listings and the manufacturer抯 installation instructions.
3-4.6.3
The thickness of sleeves for fire dampers shall not be less than that associated with the conditions of rating required by Section 3-4.
Exception: Where UL 555, Standard for Safety Fire Dampers, permits sleeve thickness to be the same as that of the duct gauge, such thickness shall not be less than that specified in Table 3-4.6.3.

Table 3-4.6.3 Minimum Sleeve Thickness Permitted in Accordance with UL 555

Air Duct Diameter or Maximum Width Minimum Sleeve Thickness
in. mm in. gauge
12 or less 305 0.018 26
13-30 330-762 0.024 24
31-54 787-1372 0.030 22
55-84 1397-2134 0.036 20
85 or more 2159 0.047 18

3-4.6.4
Where air ducts pass through walls, floors, or partitions that are required to have a fire resistance rating and where fire dampers are not required, the opening in the construction around the air duct shall be as follows:
(1) Not exceeding a 1-in. (2.54-cm) average clearance on all sides
(2) Filled solid with an approved material capable of preventing the passage of flame and hot gases sufficient to ignite cotton waste when subjected to the time-temperature fire conditions required for fire barrier penetration as specified in, NFPA 251, Standard Methods of Tests of Fire Endurance of Building Construction and Materials
Exception: Where fire dampers are installed, proper clearance for expansion shall be maintained. (See 3-4.6.)

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3-4.7 Maintenance.
At least every 4 years, fusible links (where applicable) shall be removed; all dampers shall be operated to verify that they fully close; the latch, if provided, shall be checked; and moving parts shall be lubricated as necessary.

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4-1 Wiring.
The installation of electrical wiring and equipment associated with the operation and control of air-conditioning and ventilating systems shall be in accordance with NFPA 70, National Electrical Code.
4-2 Manual Control.
Each air distribution system shall be provided with at least one manually operable means for stopping the operation of the supply, return, and exhaust fan(s) in an emergency. The means of manual operation shall be located at an approved location.
4-3* Smoke Dampers.
4-3.1
Smoke dampers shall be controlled by an automatic alarm initiating device. Smoke dampers shall be permitted to be positioned manually from a command station.
4-3.2
Smoke dampers installed to isolate the air-handling system in accordance with 2-3.9.2 shall be arranged to close automatically when the system is not in operation.
4-3.3*
Smoke dampers installed in smoke barriers shall be permitted to remain open during fan shutdown, provided their associated controlling damper actuators and smoke detectors remain operational.

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4-4* Smoke Detection for Automatic Control.
4-4.1 Testing.
All automatic shutdown devices shall be tested at least annually.
4-4.2* Location.
Smoke detectors listed for use in air distribution systems shall be located as follows:
(1) Downstream of the air filters and ahead of any branch connections in air supply systems having a capacity greater than 2000 ft3/min (944 L/sec)
(2) At each story prior to the connection to a common return and prior to any recirculation or fresh air inlet connection in air return systems having a capacity greater than 15,000 ft3/min (7080 L/sec) and serving more than one story
Exception No. 1: Return system smoke detectors shall not be required where the entire space served by the air distribution system is protected by a system of area smoke detectors.
Exception No. 2: Fan units whose sole function is to remove air from the inside of the building to the outside of the building.
4-4.3* Function.
Smoke detectors provided as required by 4-4.2 shall automatically stop their respective fan(s) on detecting the presence of smoke.
Exception: Where the return air fan is functioning as part of an engineered smoke-control system and a different mode is required.

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明天继续，发太多了

梅西

好深噢！！！

芒果

太长了，这个好像用到的不多，可能是我们公司太小了呵呵

neil0413

不错啊
有电子档更好啊呵呵